FixPluginTypesSerialization

Hook into the native Unity engine for adding BepInEx plugin assemblies into the assembly list that is normally used for the assemblies sitting in the game Managed/ folder.

This solve a bug where custom Serializable structs and such stored in plugin assemblies are not properly getting deserialized by the engine.

Installation

• Copy the BepInEx\patchers\FixPluginTypesSerialization folder into your BepInEx/patchers folder.

Adding your own Unity version support

This project only works with official releases of Unity 64 bit versions from 5.0.0 to 2023.2.20.

If you want to add your own version, know that I don't have the free time and the will to investigate on how to help you, instead, here is a small guide for updating the project yourself:

• Get IDA or Ghidra and get the UnityPlayer PDB from the official Unity Symbol Server.
• Read the pseudo C code from the decompiler.
• Find the Assembly Lists they populate from the Managed/ folder.
• Add the BepInEx plugins folder assemblies to those Assembly Lists.

If the game uses custom Unity version or it's not supported and doesn't have pdb you can manually change offsets in the config:

• It's not trivial, and your best bet would be getting the closest release verison that has a pdb and open it in IDA/Ghidra.
• Find the functions you need by name, then search for the bytes of the function in your Unity version.
• The start address of the function would be your offset (at least in ghidra just the address is not the offset, you would also need to look at the start of the file and sse the first address and subtract that from your function address to get the offset).

That's basically what this project does.

Please note that Unity's implementation can vary significantly from one version to another; therefore, you may need to completely rethink your approach for a given supported version.

Note about Virtual File System

An alternative path to messing with Unity internals directly is to investigate on how to setup a Virtual File System, other modding communities like Skyrim have done it for mod management purposes.

The idea is to redirect all system calls so that the bepinex plugin folder is treated as if it were located in the “Managed” folder.

Special Thanks

• Horse for the original code base

• 0x0ade for the NativeLibraryHelper class

• knah

• KingEnderBrine

• Twiner

• NebNeb for the icon